Axial Muscles

Question 1

Erector Spinae

Answer 1

spinalis group: medial
longissimus group: intermediate
iliocostalis group: lateral

Question 2

splenius capitis

Answer 2

function: extends head (bilaterally) laterally flexes or rotates head same side as contracting muscles and extend vertebral column (unilaterally)

Question 3

semispinalis capitis

Answer 3

function: bilaterally extend head and unilaterally rotate head opposite side and extend vertebral column

Question 4

rotatores

Answer 4

function: bilaterally weakly extend vertebral column and unilaterally weakly rotate vertebral column to side opposite

Question 5

interspinales

Answer 5

function: bilaterally weakly extend vertebral column unilaterally stabilize vertebral column

Question 6

intertransversarii

Answer 6

function: bilaterally weakly extend vertebral column, unilaterally stabilize vertebral column during movement
laterally flex vertebral column

Question 7

quadratus lumborum

Answer 7

innervation: N/A
origin: iliac crest
insertion: 12th rib and transverse processes of lumbar vertebrae
function: depresses 12th rib, unilaterally raises pelvis, stabilizes lumbar, helps with lateral lumbar flexion

Question 8

external oblique

Answer 8

bilaterally compress abdomen and flex vertebral column, unilaterally laterally flex vertebral column (especially lumbar portion) and rotate vertebral column

Question 9

internal oblique

Answer 9

bilaterally compress the abdomen and flex vertebral column, unilaterally laterally flex and rotate vertebral column

Question 10

rectus abdominis

Answer 10

flexes vertebral column and compresses abdomen to aid in defecation, vomiting, childbirth, urination, forced exhalation RMA: flexes pelvis

Question 11

transverse abdominis

Answer 11

compresses abdomen

Question 12

external intercostals

Answer 12

elevation of ribs in inhalation

Question 13

internal intercostals

Answer 13

depression of ribs in exhalation

Question 14

diaphragm

Answer 14

contraction: flattens and increases volume in thoracic cavity for inhalation
relaxation: domed and decreases volume in thoracic cavity

Question 15

external urethral sphincter

Answer 15

helps expel last drops of urine and semen

innervation: pudendal

Question 16

bulbospongiosus

Answer 16

helps expel urine and propel semen along the urethra, assists in erection in males and females, constricts vaginal orifice
innervation: pudendal

Question 17

external anal sphincter

Answer 17

keeps anal canal closed

innervation: pudendal

Question 18

coccygeus

Answer 18

draws coccyx forward during defecation adn childbirth

Question 19

levator ani

Answer 19

iliococygeus, pubococcygeus, puborectalis

Question 20

iliococcygeus

Answer 20

resists intra-abdominal pressure during forced exhalation, coughing, vomiting, defecation, childbirth, urination; constricts anus, urethra, and vagina

Question 21

pubococcygeus

Answer 21

resists intra-abdominal pressure during forced exhalation, coughing, vomiting, defecation, childbirth, urination; constricts anus, urethra, and vagina

Question 22

puborectalis

Answer 22

helps maintain fecal continence and assists in defecation